Research data gathering with a portable monitor and a stationary device

ABSTRACT

Methods and apparatus for research data gathering with a portable monitor and a stationary device are described. An example method includes gathering, via a stationary monitoring system, first data concerning exposure to media output by a media receiver, wherein gathering the first data comprises collecting a first code encoded in the media, gathering second data concerning exposure to the media output by the media receiver with a portable monitor carried on the person of a user, wherein the second data comprises a second code encoded in the media, gathering, via the portable monitor, location data encoded in the media by the stationary monitoring system, the location data providing information on a physical location of the portable monitor, and producing the audience measurement data concerning exposure to the media output by the receiver from the first data, the second data, and the location data.

This patent arises from a continuation of U.S. patent application Ser.No. 11/935,788, filed Nov. 6, 2007, which claims the benefit of U.S.provisional patent application Ser. No. 60/857,714, filed on Nov. 7,2006, and which arises from a continuation-in-part of U.S. Pat. No.7,483,975, filed on Mar. 26, 2004 and granted Jan. 27, 2009. U.S. patentapplication Ser. Nos. 11/935,788 and 60/857,714 and U.S. Pat. No.7,483,975 are hereby incorporated by reference in their entirety.

Systems and processes for use in gathering research data using aportable monitor and a stationary device are disclosed.

FIG. 1 is a functional block diagram illustrating certain embodiments ofa system for gathering research data using a portable monitor and astationary device;

FIG. 2 is a functional block diagram illustrating an operation ofcertain ones of the FIG. 1 embodiments to emit an acoustic location codeand/or a presence code;

FIG. 3 is a flow diagram of certain embodiments for communicatinglocation codes according to a “step-down” method;

FIG. 4 depicts certain embodiments of a monitoring system comprising astationary monitor and a portable monitor;

FIG. 5 is a functional a block diagram of a directional acousticlocation code producing technique employed in certain embodiments;

FIG. 6 is a block diagram illustrating techniques for producingdirectional location codes based on code characteristics;

FIG. 7 illustrates certain techniques for producing codes in astationary device and/or in a portable monitor;

FIG. 8 Illustrates certain embodiments in which a portable monitor iscoupled with a communication adapter enabling the portable monitor toreceive location data from a stationary monitor;

FIG. 9 illustrates certain embodiments of the communications adapter ofFIG. 8;

FIG. 10 illustrates a portable monitor having separate receivers forreceiving ancillary codes and location codes;

FIG. 10A illustrates a portable monitor having a single receiver forreceiving ancillary codes and location codes;

FIG. 11 illustrates a monitoring system in which a panelist carries twoportable devices;

FIG. 11A illustrates a system for consolidating and communicating thedata gathered by the portable devices of FIG. 11;

FIG. 12 illustrates a code reading and matching process for determiningwhether a panelist is in an area proximate to a stationary monitor;

FIG. 13 illustrates a signature extracting and matching process fordetermining whether a panelist is in an area proximate to a stationarymonitor;

FIG. 14 is used in explaining an audio signature extraction process.

For this application the following terms and definitions shall apply:

The term “data” as used herein means any indicia, signals, marks,symbols, domains, symbol sets, representations, and any other physicalform or forms representing information, whether permanent or temporary,whether visible, audible, acoustic, electric, magnetic, electromagneticor otherwise manifested. The term “data” as used to representpredetermined information in one physical form shall be deemed toencompass any and all representations of corresponding information in adifferent physical form or forms.

The terms “media data” and “media” as used herein mean data which iswidely accessible, whether over-the-air, or via cable, satellite,network, internetwork (including the Internet), print, displayed,distributed on storage media, or by any other means or technique that ishumanly perceptible, without regard to the form or content of such data,and including but not limited to audio, video, audio/video, text,images, animations, databases, broadcasts, displays (including but notlimited to video displays, posters and billboards), signs, signals, webpages, print media and streaming media data.

The term “research data” as used herein means data comprising (1) dataconcerning usage of media data, (2) data concerning exposure to mediadata, and/or (3) market research data.

The term “presentation data” as used herein means media data, contentother than media data or a message to be presented to a user.

The term “ancillary code” as used herein means data encoded in, addedto, combined with or embedded in media data to provide informationidentifying, describing and/or characterizing the media data, and/orother information useful as research data.

The term “reading” as used herein means a process or processes thatserve to recover research data that has been added to, encoded in,combined with or embedded in, media data.

The term “database” as used herein means an organized body of relateddata, regardless of the manner in which the data or the organized bodythereof is represented. For example, the organized body of related datamay be in the form of one or more of a table, a map, a grid, a packet, adatagram, a frame, a file, an e-mail, a message, a document, a report, alist or in any other form.

The term “network” as used herein includes both networks andinternetworks of all kinds, including the Internet, and is not limitedto any particular network or inter-network.

The terms “first”, “second”, “primary” and “secondary” are used todistinguish one element, set, data, object, step, process, activity orthing from another, and are not used to designate relative position orarrangement in time, unless otherwise stated explicitly.

The terms “coupled”, “coupled to”, and “coupled with” as used hereineach mean a relationship between or among two or more devices,apparatus, files, circuits, elements, functions, operations, processes,programs, media, components, networks, systems, subsystems, and/ormeans, constituting any one or more of (a) a connection, whether director through one or more other devices, apparatus, files, circuits,elements, functions, operations, processes, programs, media, components,networks, systems, subsystems, or means, (b) a communicationsrelationship, whether direct or through one or more other devices,apparatus, files, circuits, elements, functions, operations, processes,programs, media, components, networks, systems, subsystems, or means,and/or (c) a functional relationship in which the operation of any oneor more devices, apparatus, files, circuits, elements, functions,operations, processes, programs, media, components, networks, systems,subsystems, or means depends, in whole or in part, on the operation ofany one or more others thereof.

The terms “communicate,” “communicating” and “communication” as usedherein include both conveying data from a source to a destination, anddelivering data to a communications medium, system, channel, network,device, wire, cable, fiber, circuit and/or link to be conveyed to adestination. The term “communications” as used herein includes one ormore of a communications medium, system, channel, network, device, wire,cable, fiber, circuit and link.

The term “processor” as used herein means processing devices, apparatus,programs, circuits, components, systems and subsystems, whetherimplemented in hardware, software or both, and whether or notprogrammable. The term “processor” as used herein includes, but is notlimited to one or more computers, hardwired circuits, signal modifyingdevices and systems, devices and machines for controlling systems,central processing units, programmable devices and systems, fieldprogrammable gate arrays, application specific integrated circuits,systems on a chip, systems comprised of discrete elements and/orcircuits, state machines, virtual machines, data processors, processingfacilities and combinations of any of the foregoing.

The terms “storage” and “data storage” as used herein mean one or moredata storage devices, apparatus, programs, circuits, components,systems, subsystems, locations and storage media serving to retain data,whether on a temporary or permanent basis, and to provide such retaineddata.

The terms “panelist,” “respondent” and “participant” are interchangeablyused herein to refer to a person who is, knowingly or unknowingly,participating in a study to gather information, whether by electronic,survey or other means, about that person's activity.

The term “household” as used herein is to be broadly construed toinclude family members, a family living at the same residence, a groupof persons related or unrelated to one another living at the sameresidence, and a group of persons (of which the total number ofunrelated persons does not exceed a predetermined number) living withina common facility, such as a fraternity house, an apartment or othersimilar structure or arrangement, as well as such common residence orfacility.

The term “portable user appliance” (also referred to herein, forconvenience, by the abbreviation “PUA”) as used herein means anelectrical or non-electrical device capable of being carried by or onthe person of a user or capable of being disposed on or in, or held by,a physical object (e.g., attaché, purse, clothing) capable of beingcarried by or on the user, and having at least one function of primarybenefit to such user, including without limitation, a cellulartelephone, a personal digital assistant (“PDA”), a Blackberry® device, aradio, a television, a game system (e.g., a Gameboy® device), a notebookcomputer, a laptop computer, a GPS device, a personal audio device(e.g., an MP3 player, an iPod® device), a DVD player, a two-way radio, apersonal communications device, a telematics device, a remote controldevice, a wireless headset, a wristwatch, a portable data storage device(e.g., Thumb™ drive), a camera, a recorder, a keyless entry device, aring, a comb, a pen, a pencil, a notebook, a wallet, a tool, aflashlight, an implement, a pair of glasses, an article of clothing, abelt, a belt buckle, a fob, an article of jewelry, an ornamentalarticle, a pair of shoes or other foot garment (e.g., sandals), ajacket, and a hat, as well as any devices combining any of the foregoingor their functions.

The term “research device” as used herein shall mean (1) a portable userappliance configured or otherwise enabled to gather, store and/orcommunicate research data, or to cooperate with other devices to gather,store and/or communicate research data, and/or (2) a research datagathering, storing and/or communicating device.

FIG. 1 schematically illustrates a monitoring system for monitoringusage of content presented at a predetermined location, such as within aparticular room in a household. Such content can be any one or more ofcontent 10 presented 15 by a television; a radio; a home theater system;a media center; a display coupled with a video game system, personalcomputer, video reproducing device (such as a DVD player, a personalvideo player, a digital video recorder, video tape recorder or thelike); a speaker or headphones coupled with a television, a radio, avideo game system, personal computer, hi-fi system, personal audioplayer or the like.

The monitoring system comprises a stationary device 20 and a portablemonitor 30. In certain embodiments, stationary device 20 serves toproduce location data 25 to be received by portable monitor 30 andproviding an indication of a location of the portable monitor 30proximate to the presentation 15. In certain embodiments, stationarydevice comprises a set-top box (STB) or IRR. The location data receivedby the portable monitor 30 is stored thereby and/or communicated to aprocessing facility (not shown for purposes of simplicity and clarity).In certain embodiments, the stationary device 20 carries out multiplefunctions for monitoring usage of content and/or to assist suchmonitoring. In addition to producing the location data 25, suchfunctions include reading codes present in the content, obtainingchannel selection data, people meter functions, and the like.

In certain embodiments, the portable monitor 30 also receives a wirelesssignal providing the information that the portable monitor 30 is in thehousehold of the panelist to whom it was assigned. This enables the useof a low data rate location code, since it is then only necessary todistinguish the panelist's presence in a particular one of a handful ofrooms in the household. In certain embodiments, such wireless signal isa low power RF signal encoded to inform the portable monitor 30 that itis “in home”.

In certain embodiments, stationary device 20 receives presence data fromportable monitor 30 in place of, or in addition to, producing thelocation data 25. In certain ones of these embodiments, such presencedata comprises portable monitor identification data, panelistidentification data and/or demographic data of the panelist to whom theportable monitor has been assigned.

A method of gathering data concerning a location of an audience memberproximate to a content presentation comprises providing a portablemonitor to an audience member, providing a stationary device proximateto a content presentation, and at least one of communicating locationdata to the portable monitor from the stationary device andcommunicating portable monitor and/or audience member identificationdata to the stationary device from the portable monitor.

Location data is communicated in various ways, depending on theembodiment. In certain embodiments, the location data is communicated bya wire, cable, optical fiber or the like. In certain embodiments, thelocation data is communicated wirelessly as acoustic energy (whether inthe audible frequency range, at ultrasonic frequencies and/or atsubsonic frequencies), electromagnetic energy (such as RF, infraredlight or visible light), a magnetic field and/or an electric field.

A method of gathering data concerning a location of an audience memberproximate to a content presentation comprises communicating locationdata from a stationary device proximate to the content presentation to aportable monitor carried on or with the person of an audience member,and/or communicating at least one of portable monitor identificationdata, audience member identification data and audience memberdemographic data to the stationary device.

In certain embodiments, location data and/or presence data arecommunicated as encoded acoustic energy. Various techniques for encodingaudio for producing such encoded acoustic energy, and for reading thesame, are disclosed in U.S. Pat. No. 5,764,763 to Jensen et al., U.S.Pat. No. 5,450,490 to Jensen et al., U.S. Pat. No. 5,579,124 to Aijalaet al., U.S. Pat. No. 5,581,800 to Fardeau et al., U.S. Pat. No.6,871,180 to Neuhauser, et al., U.S. Pat. No. 6,845,360 to Jensen, etal., U.S. Pat. No. 6,862,355 to Kolessar, et al., U.S. Pat. No.5,319,735 to Preuss et al., U.S. Pat. No. 5,687,191 to Lee, et al., U.S.Pat. No. 6,175,627 to Petrovich et al., U.S. Pat. No. 5,828,325 toWolosewicz et al., U.S. Pat. No. 6,154,484 to Lee et al., U.S. Pat. No.5,945,932 to Smith et al., US 2001/0053190 to Srinivasan, US2003/0110485 to Lu, et al., U.S. Pat. No. 5,737,025 to Dougherty, etal., US 2004/0170381 to Srinivasan, and WO 06/14362 to Srinivasan, etal., all of which hereby are incorporated by reference herein.

Examples of techniques for encoding data in audio that may be reproducedas encoded acoustic energy, and for reading such data, are described inBender, et al., “Techniques for Data Hiding”, IBM Systems Journal, Vol.35, Nos. 3 & 4, 1996, which is incorporated herein in its entirety.Bender, et al. disclose a technique for encoding audio termed “phaseencoding” in which segments of the audio are transformed to thefrequency domain, for example, by a discrete Fourier transform (DFT), sothat phase data is produced for each segment. Then the phase data ismodified to encode a code symbol, such as one bit. Processing of thephase encoded audio to read the code is carried out by synchronizingwith the data sequence, and detecting the phase encoded data using theknown values of the segment length, the DFT points and the datainterval.

Bender, et al. also describe spread spectrum encoding and code reading,of which multiple embodiments are disclosed in the above-cited Aijala,et al. U.S. Pat. No. 5,579,124.

Still another audio encoding and reading technique described by Bender,et al. is echo data hiding in which data is embedded in a host audiosignal by introducing an echo. Symbol states are represented by thevalues of the echo delays, and they are read by any appropriateprocessing that serves to evaluate the lengths and/or presence of theencoded delays.

A further technique, or category of techniques, termed “amplitudemodulation” is described in R. Walker, “Audio Watermarking”, BBCResearch and Development, 2004. In this category fall techniques thatmodify the envelope of the audio signal, for example by notching orotherwise modifying brief portions of the signal, or by subjecting theenvelope to longer term modifications. Processing the audio to read thecode can be achieved by detecting the transitions representing a notchor other modifications, or by accumulation or integration over a timeperiod comparable to the duration of an encoded symbol, or by anothersuitable technique.

Another category of techniques identified by Walker involvestransforming the audio from the time domain to some transform domain,such as a frequency domain, and then encoding by adding data orotherwise modifying the transformed audio. The domain transformation canbe carried out by a Fourier, DCT, Hadamard, Wavelet or othertransformation, or by digital or analog filtering. Encoding can beachieved by adding a modulated carrier or other data (such as noise,noise-like data or other symbols in the transform domain) or bymodifying the transformed audio, such as by notching or altering one ormore frequency bands, bins or combinations of bins, or by combiningthese methods. Still other related techniques modify the frequencydistribution of the audio data in the transform domain to encode.Psychoacoustic masking can be employed to render the codes inaudible orto reduce their prominence. Processing to read ancillary codes in audiodata encoded by techniques within this category typically involvestransforming the encoded audio to the transform domain and detecting theadditions or other modifications representing the codes.

A still further category of techniques identified by Walker involvesmodifying audio data encoded for compression (whether lossy or lossless)or other purpose, such as audio data encoded in an MP3 format or otherMPEG audio format, AC-3, DTS, ATRAC, WMA, RealAudio, Ogg Vorbis, APTX100, FLAC, Shorten, Monkey's Audio, or other. Encoding involvesmodifications to the encoded audio data, such as modifications to codingcoefficients and/or to predefined decision thresholds. Processing theaudio to read the code is carried out by detecting such modificationsusing knowledge of predefined audio encoding parameters.

It will be appreciated that various known encoding techniques may beemployed, either alone or in combination with the above-describedtechniques. Such known encoding techniques include, but are not limitedto FSK, PSK (such as BPSK), amplitude modulation, frequency modulationand phase modulation.

FIG. 2 is a functional block diagram for illustrating an operation ofthe stationary device 20 to produce acoustic location data within theaudible frequency range and an operation of the portable monitor 30 toproduce acoustic portable monitor identification data, acoustic audiencemember identification data and/or demographic data within the audiblefrequency range. In the embodiments of FIG. 2, the acoustic data ismasked so that it is inaudible to human hearing. Ambient acoustic energyis sampled 25 by an acoustic transducer of the stationary device 20and/or the portable monitor 30 (not shown for purposes of simplicity andclarity). The sampled acoustic energy is evaluated 40 to assess itsability to mask acoustic codes communicated in the vicinity ofstationary device 20 and the portable monitor 30. The masking evaluationis carried out in accordance with psychoacoustic masking principles. Incertain embodiments, one or more of tonal masking, narrow-band maskingand broadband masking effects are evaluated to produce evaluation datafrom which code magnitudes at various frequencies may be selected suchthat, the codes remain inaudible when reproduced as sound but haveadvantageously high magnitudes to assist in distinguishing them fromnoise. In certain embodiments, two or more such masking evaluations areadded to determine the permissible code magnitudes. In certainembodiments, the masking evaluation is carried out in accordance withtechniques disclosed in U.S. Pat. No. 5,764,763 assigned to the assigneeof the present application and incorporated herein by reference in itsentirety.

The masking evaluation produces masking data indicating permissiblemagnitudes, frequencies, timings and/or durations of the acoustic datato be produced and/or of various portions or components thereof. Themasking data is supplied to an acoustic data generator 50 which respondsby generating the acoustic location or identification data so that it ismasked to human hearing.

FIG. 3 is a flow diagram illustrating certain embodiments in which thestationary device 20 communicates encoded location data to the portablemonitor 30 as inaudible acoustic energy within the audible frequencyband, and in a manner that assists the portable monitor 30 todistinguish encoded acoustic energy produced within the same room as theportable monitor from acoustic codes produced in other rooms that arenevertheless picked up by portable monitor 30. More particularly, theembodiments of FIG. 3 employ a “step-down” code in which the code energycontent is reduced in a step-wise fashion throughout some period oftime. When the period of time expires, the code energy is restored to aprevious maximum level and the step-down process is repeated. Thisprocedure is repeated so long as the acoustic code is being produced. Inthe event that the portable monitor receives two such codes during thesame interval, it selects the code successfully read at the lowestenergy level as representing the location of the portable monitor (andthus the panelist carrying it). This technique takes advantage ofattenuation of acoustic codes as they pass through walls to distinguishcodes produced in the same room as the portable monitor 30.

As shown in FIG. 3, the encoding process is commenced 100 byinitializing energy parameters, such as data representing a maximum codeenergy level and the energy reduction or level at each or various onesof the steps. As also indicated at 100, a timer A is initiated at acount representing a duration of each step and a timer B is initiated ata count representing a duration of the time period for completing thestep-down procedure. The masking ability of the ambient acoustic energyand/or acoustic presentation data adjacent a speaker of the presentation15 is evaluated 110 and stationary device 20 produces 120 an acousticlocation code based both on the masking evaluation 110, a current energyparameter. During the first pass through the process of FIG. 3, thecurrent energy parameter is set at a maximum level. During subsequentpasses through the process and until completion of the step-downprocedure, the current energy parameter is adjusted to progressivelylower levels at the completion of each step.

At 130, timer A is checked to determine if it has timed out. If not,processing returns to 110 to continue producing the acoustic code usingunmodified parameters. If the timer has timed out (that is, timer=0),which represents an end of a current step, the timer is reset 140 andthe current energy parameter is reduced to the level for the next step.At 160, timer B is checked to determine if it has timed out. If not,processing returns to 110 to continue producing the code at the reducedenergy level represented by the current energy parameter set at 150.However, if timer B has timed out, which represents the end of thecurrent step-down procedure, timer B is reset 170 and the current energyparameter is restored 180 to a value representing the maximum codeenergy level.

In certain ones of the FIG. 3 embodiments, the current energy parameteris replaced by a scale factor that is applied to data representing theambient acoustic energy or the acoustic energy of the presentation dataadjacent a speaker, so that for each step following the first, suchenergy data is reduced by the scale factor. This will automaticallyresult in a reduction of the code energy, since the capacity of acousticenergy to mask a code is reduced as the amount of such acoustic energyis reduced.

In certain ones of the FIG. 3 embodiments, the code energy level isreduced by a predetermined amount, such as 5 dB every 10 seconds, untilthe step-down procedure is completed. In a particular encoding techniqueemployed in certain ones of the FIG. 3 embodiments, the stationarymonitor 20 regenerates the presentation data picked up at the speakerincluding a sequence of code symbols each as a unique combination ofsingle-frequency code components so that the code is masked by theregenerated presentation data. In certain ones of such embodiments, thecode symbols are produced as disclosed in U.S. Pat. No. 5,764,763,assigned to the assignee of the present application and herebyincorporated herein by reference. The encoded, regenerated presentationdata is reproduced acoustically after an indiscernible delay, forexample, a delay of less than 30 ms. In certain ones of theseembodiments in which the portable monitor 30 is able to unambiguouslysample the ambient acoustic energy up to X kHz and reads broadcast codesat frequencies up to X-Y kHz (where X and Y are positive, and X>Y), thecode components generated by the stationary monitor fall in the rangeX-Y kHz to X kHz. In such embodiments, the presentation data is sampledat a tweeter or mid-range speaker of the presentation, as appropriate.In other ones of such embodiments, the code components produced by thestationary device 20 are included at frequencies below X-Y kHz that arenot used by such broadcast codes. Any of the other encoding techniquesdescribed hereinabove may be used in place of that disclosed by U.S.Pat. No. 5,764,763.

In certain embodiments, in place of an audible frequency band code, thetechnique of FIG. 3 employs an ultrasonic acoustic code.

FIG. 4 depicts a monitoring system comprising a stationary monitor 220and a portable monitor 240 carried on the person of a panelist presentin the same room of a household as a content selection and presentationsystem comprising a content selector 210 and a presentation device 230.A source of content 200 may be present in the same room or may belocated elsewhere. The presentation device may be a device such as atelevision, a video game system, a hi-fi system, a radio, a personalcomputer, a video and/or audio player, a home theater system, a mediacenter and the like.

The content source 200 may be local or remote. It may be a cabletelevision system, satellite television system, video and/or audiorecorder or player, game system, personal computer, or other contentdelivery network, such as the Internet.

The content selector 210 may be a cable box, a satellite box, a contentdistribution system, a digital entertainment center or the like.

The content source 200, content selector 210 and presentation device 230may be separate, or two or more may be embodied in a single device.

The monitoring system 220 receives audio data 240 from the contentselector 210, either as baseband data, audio IF, broadcast data orotherwise encoded audio data.

As will be explained below, the acoustic location data 250 comprisesdata in the audible frequency range and it is masked, using the methodsdescribed above, to ensure it will be inaudible, imperceptible or atleast inconspicuous. The acoustic location data 250 is added to or usedto modify audio data 240 in some other fashion to encode locationinformation in audio data, and finally reproduced as acoustic contentdata 260.

The monitoring system 220 evaluates a masking ability of the receivedaudio data and, based on such evaluation, produces acoustic locationdata 250 indicating a location of presentation device 230, (e.g., atelevision in a particular room within a household). The monitoringsystem 220 then supplies the acoustic location data 250 to the contentselector 210 or the presentation device 230 to be added to the audiodata 240 and reproduced as encoded acoustic content data 260 from thepresentation device 230 to the portable monitor 240.

As an alternative, the monitoring system 220 receives audio data 240from the content source 200 and supplies the acoustic location data 250to the content source 200, content selector 210 or presentation device230 to be added to audio data 240.

As another alternative, the monitoring system 220 receives audio data240 from content source 200 or content selector 210, produces acousticlocation data 250, adds it to the audio data 240 or modifies the audiodata 240 based on the acoustic location data 250, to encode the audiodata 240 and supplies the encoded audio data to the presentation device230, the content selector 210 or the content source 200 as a replacementfor the original audio data 240.

The monitoring system 220 may include a channel or source monitoringfunction, and/or a content identification function, and may beimplemented by decoding data encoded in audio and/or video of content,and/or by extracting audio and/or video signatures for matching withsignatures representing content whose source and/or content is known.

The portable monitor 240 picks up the acoustically reproduced audio,decodes the location data therein, and stores it with a time stamp. Thestored data is communicated to a processing facility where it is used toproduce reports of audience size and composition (demographics).

FIG. 5 is a functional block diagram of a directional acoustic locationcode producing technique employed in certain embodiments of stationarydevice 20 of FIG. 1 employing a directional acoustic transducer 430 toenable limiting detectability of acoustic codes to the area in front ofa presentation device, such as a television. Accordingly, for a givenportable monitor 440 carried on the person of a panelist to read suchlocation codes, the panelist must be in a predetermined area in front ofthe presentation device.

Codes are generated 420 for driving transducer 430 either in the audiblefrequency range or at ultrasonic frequencies. The codes may be producedin any of the ways explained hereinabove, as well as still further waysknown in the art.

In certain embodiments, the ambient acoustic energy is sampled in step400 and its masking ability is evaluated in step 410. These two stepsare optional, depending on code characteristics. Where masking isemployed, data representing the masking abilities of the ambientacoustic energy is supplied for use in generating a code that will bemasked when reproduced as acoustic energy by transducer array 430. Withcertain code techniques, PSK, FSK, or the like, masking 410 ispreferable to avoid audibility. Acoustic spread spectrum codes that haveindividual frequency components of low magnitude might not requiremasking 410, depending on their energy levels and frequencies. Low levelacoustic pulses of short duration might also not require masking 410 ifthey are sufficiently short in duration.

In certain embodiments the directional transducer 430 comprises a phasedarray of acoustic transducers. In other embodiments, the directionaltransducer 430 comprises an acoustic transducer arranged at the focus ofa parabolic reflector. In other embodiments, the directional transducer430 comprises an acoustic transducer in combination with other kinds offocusing devices, such as piezoelectric flat panel focusing devices.

In certain embodiments, the directional transducer 430 comprises anarray of ultrasonic transducers arranged to produce a directionalultrasonic beam when excited with ultrasonic energy. The ultrasonicenergy is amplitude modulated with a location code in the audiblefrequency range. Amplitude modulation results in the production of twoultrasonic frequencies that heterodyne in the air to produce thelocation code in the audible frequency band with the directionalcharacteristics of the ultrasonic beam.

In certain embodiments, the portable monitor 440 having an acoustictransducer for receiving inaudible broadcast codes in the frequencyrange of 1 to 3 kHz, receives acoustic location codes at frequenciesabove 3 kHz. Stationary device 20 is arranged to produce such acousticlocation codes with directional transducer 430 to be received by theacoustic transducer of portable monitor 440. Higher frequency acousticcodes are in general more convenient for achieving directionaltransmission of the codes and are attenuated to a greater extent thanlower frequency acoustic codes when passing through walls, thusassisting in avoiding “spillover” of location codes into other rooms.

FIG. 6 is a block diagram illustrating techniques for producingdirectional location codes based on the characteristics of code signalsused to excite a speaker/transducer 560. A plurality of single frequencycode components 530 and 540 are produced, each of which is harmonicallyrelated to at least one of the other components and is produced so thatit is in phase with the other as supplied to the speaker 560. Because ofthe harmonic relationship of each code component 530 and 540 and becausethey are in phase as supplied to the speaker, they remain in phase infront of the speaker, so that they are detectable by portable monitor550. However, as portable monitor 550 is moved away from the area infront of the speaker, the components 530 and 540 become out of phase andalso experience increased interference from multipath (i.e., reflected)components, so that they ultimately become undetectable by portablemonitor 550. To the extent that the components 530 and 540 pass througha wall, they become further attenuated and their phase relationshipbecomes further distorted, so that detection in other rooms can beprevented or substantially impaired.

In certain embodiments, the ambient acoustic energy is sampled in step500 and its masking ability is evaluated in step 510. These two stepsare optional, depending on code characteristics. The masking ability 510of ambient acoustic energy is evaluated in some embodiments to ensureinaudibility or suppressed audibility of location codes. Ambientacoustic sampling 500 and masking evaluation 510 may be unnecessary ifcode components are kept below the absolute human audibility thresholdat the frequency of each respective code component 530 and 540 or ifthey are slightly audible and nevertheless deemed acceptable.

Code parameters 520 may control one or more of the following: (1)selection of groups of code components, each having a differentfrequency, to encode different symbols and symbol sequences representingthe location code, (2) selection of component durations to representlocation information or to ensure masking, and (3) selection ofcomponent magnitudes to ensure masking or to encode locationinformation. Note that while only two code components 530 and 540 areillustrated in FIG. 6, it will be appreciated that any finite number ofcode components greater than one may be used.

In certain embodiments, acoustic location codes are produced in thestationary device 20 and/or acoustic identification and/or panelistdemographics codes are produced in the portable device 30. FIG. 7illustrates certain techniques for producing such codes in stationarydevice 20 and/or in portable monitor 30. Code parameters are selected620 to: (1) reduce spillover of codes into other rooms to an acceptablylow level and (2) to maintain codes either inaudible or withcharacteristics that, while audible to some extent, are neverthelessdeemed acceptable. In certain embodiments, such code parameters includeone or more of (1) code magnitude and/or code component magnitudes, (2)code duration and/or code component durations, and (3) code frequency orfrequencies.

In certain embodiments, the ambient acoustic energy is sampled 600 andthe masking ability of such energy is evaluated 610. These two steps areoptional, depending on code characteristics. The masking ability ofambient acoustic energy is evaluated in some embodiments to ensureinaudibility or suppressed audibility of location codes. Ambientacoustic sampling 600 and masking evaluation 610 may be unnecessary ifcode components are kept below the absolute human audibility thresholdat the frequency of each respective code component or if they areslightly audible and deemed acceptable.

In certain embodiments, certain types of encoding techniques produce lowlevel acoustic codes in the audible frequency band that are perceived,if at all, as noise. Therefore, these low level acoustic codes may beacceptable for use as location codes even without taking measures toensure that the codes will be inaudible. These encoding techniquesinclude various spread spectrum encoding techniques, such as directsequence spread spectrum encoding and frequency hopping spread spectrumencoding.

In certain embodiments, the acoustic codes are produced as a sequence ofcode symbols in a manner similar to the techniques disclosed in U.S.Pat. No. 5,764,763 issued Jun. 9, 1998, in the name of James M. Jensenet al., which is incorporated by reference herein in its entirety, thatis, in which each symbol is represented by a unique combination ofsingle frequency code components. Masking 610 is used in embodimentsthat employ such codes to ensure inaudibility. In certain ones of suchembodiments, the frequencies of the code components are within a rangeof audible frequencies that also accommodate broadcast codes of the kinddisclosed in U.S. Pat. No. 5,764,763, but which fall within frequencybins not used by such broadcast codes. Further techniques that permitencoding of such location codes and identification codes in the samefrequency range as such broadcast codes are disclosed in U.S. Pat. No.6,845,360 issued Jan. 18, 2005, in the name of James J. Jensen et al.,which is assigned to the assignee of the present application and isincorporated by reference herein it its entirety.

In certain embodiments, the same method as indicated in the aboveparagraph is used but inserts the code frequency components atfrequencies above those used to encode the broadcast codes, such as 3kHz to 4 kHz. This range is not exclusive of higher frequency ranges.The use of location codes and identification codes at higher audiblefrequencies helps avoid problems with “spillover”, since higherfrequency acoustic energy is attenuated to a greater extent as it passesthrough walls. However, any of the encoding techniques describedhereinabove may be used in place of or in addition to those described inU.S. Pat. No. 5,764,763 and U.S. Pat. No. 6,845,360.

In certain embodiments, the location codes andidentification/demographics codes are produced as one or moreband-limited or short-duration pulses in the audible frequency range.These can be used in systems that also detect broadcast codes such asthose disclosed in U.S. Pat. No. 5,764,763, by selecting the bands forthe pulses to fall outside the frequency bins used to encode thebroadcast codes, either by selecting unused bands within the same rangeof frequencies as the broadcast codes or by using bands outside suchfrequency range. If pulse duration is less than 200 ms, the sensitivityof the human ear to the pulse is reduced, as represented by a higherthreshold of audibility. Accordingly, such pulses can be kept inaudible,with or without masking by ambient acoustic energy, by keeping theirduration shorter than 200 ms and ensuring that their Sound PressureLevels (SPL) do not exceed the increased threshold of audibility at suchshort duration and for the frequency band in which the pulse isconfined.

The location or identification information can be encoded in a number ofways: (1) pulse repetition rate or periodicity, (2) pulse duration, (3)selection of pulse frequency or frequencies, (4) combinations of theforegoing, and (5) patterns of repetition rates, pulse durations andpulse frequencies. Detection of the pulses in the portable monitor 30 orstationary device 20 can be carried out by a correlation analysis.

In certain embodiments, after conversion of the sampled acoustic energyto digital form, the digitized samples are band-pass filtered (by one ormore digital filters or time-to-frequency transformation and selectionof resulting data with the desired band or bands). Then the band-limiteddata is correlated with stored versions of the pulses (or single pulse)to be detected. One simplified form of correlation analysis converts theband-limited data to binary amplitude values (e.g., by comparison to athreshold) and correlates the binary amplitude values with stored binaryversions of the pulse or pulses to be detected.

Certain embodiments employ ultrasonic acoustic location codes emittedfrom the stationary device 20 containing data to be received by theportable monitor 30. FIG. 8 illustrates a portable monitor 700 adaptedto be carried on the person of an audience member and operative to pickup acoustic codes in the audible frequency range, such as ancillarycodes included in broadcasts reproduced acoustically by a presentationdevice. Portable monitor 700 comprises communications 710 for receivingdata communications in the form of RF, infrared, acoustic, magneticand/or electric field signals, but which is not capable of receiving theultrasonic location codes from stationary device 20.

A communications adapter 720 accompanies portable monitor 700 as it iscarried on the person of a panelist. In certain embodiments,communications adapter 720 is carried in or on an enclosure of portablemonitor 700 (such as in the form of an adhesively affixed device orincorporated in a cover for the portable monitor 700, such as a “skin”).In certain embodiments, communications adapter 720 is carried on or by adevice used by the panelist to carry portable monitor 700, such as alanyard. In certain embodiments, communications adapter is carried onthe person of the panelist who also carries the portable monitor 700.

FIG. 9 illustrates an embodiment of communications adapter 720 for usewith a portable monitor 700 in which communications 710 comprises an RFreceiver. Communications adapter 720 serves to receive ultrasonic codesfrom stationary device 20 with an ultrasonic transducer 730, to decode740 the received codes to recover location data encoded thereby, toreformat 750 the location data to a form that can be processed byportable monitor 700 and to communicate the reformatted location data tocommunications 710 of portable monitor 700 by RF using an RF transmitter760. In certain ones of such embodiments, the ultrasonic transducer 730receives a 40 kHz ultrasonic location code from stationary device 20.The received codes are decoded 740 by downconverting the ultrasoniccodes to 256 Hz data. If necessary, the decoded data is further decodedand/or reformatted 750 and supplied to modulate an RF carrier fortransmission to communications 710 of portable monitor 700.

In certain embodiments of communications adapter 720, the output ofultrasonic transducer 730 is not decoded, but rather modulates a carrierin RF transmitter 760, or an infrared carrier used to drive an infraredemitter to be received by a light detector of communications 710 (notshown for purposes of simplicity and clarity). In certain embodiments,communications adapter 720 stores decoded and/or reformatted locationdata in storage (not shown for purposes of simplicity and clarity), andsubsequently reads the stored codes from the storage and communicatesthem to communications 710. In certain embodiments, RF transmitter 760is replaced by an acoustic transducer, an infrared light emitter, amagnetic or electric field producing device, or other wired or wirelessdata communication device compatible with communications 710 tocommunicate data from communications adapter 720 to communications 710.

FIG. 10 illustrates an embodiment in which a portable monitor 800 iscarried on the person of a panelist in the same room as stationarydevice 20. Portable monitor 800 serves to receive ancillary codesencoding a selected channel, station, or other source of content,content identification or other characterizing data at a first receiver810, and to receive a location code from stationary device 20 at asecond receiver 820. Data received by the first and second receivers 810and 820 is supplied to processing and storage 830 to be read and storedfor subsequent communication to a processing facility by communications840. In certain embodiments, the first receiver 810 comprises anacoustic transducer that receives ambient acoustic energy and suppliesit to processing and storage 830 where it is processed to read anyancillary codes present in the ambient acoustic energy. Any suchancillary codes that can be read are stored with a time stamp. Incertain embodiments, the second receiver 820 comprises an ultrasonictransducer, an infrared detector and/or an RF receiver to receivelocation codes from stationary monitor 20 which the second receiver 820supplies to processing and storage 830 where they are read. Any suchlocation codes that can be read are stored with a time stamp.

FIG. 10A illustrates a modification of the portable monitor 800according to further embodiments, indicated as 800′ in FIG. 10A, whichcomprises a single receiver 850, in place of receivers 810 and 820 ofthe FIG. 10 embodiment. In certain ones of the embodiments of FIG. 10A,the receiver 850 receives both ancillary codes and location codes fromstationary monitor 20 which transmits the codes either as acousticenergy (whether in the audible frequency range or as ultrasonicfrequencies), RF energy or infrared energy, in a way that processing andstorage 830 can distinguish the location codes and ancillary codes. Incertain ones of such embodiments, the ancillary codes and location codesare communicated by stationary monitor 20 as separate message layersaccording to a technique disclosed in U.S. Pat. No. 6,845,360 to Jensen,et al. assigned to the assignee of the present application and herebyincorporated herein by reference. The separate message layers are bothreceived by receiver 850 which comprises an acoustic transducer. Incertain ones of such embodiments, the ancillary codes and location codesare both communicated as acoustic energy to receiver 850, in the audiblefrequency range, at ultrasonic frequencies or both, but in separatefrequency bands. In certain ones of such embodiments, the ancillarycodes and location codes are both communicated from stationary monitor20 as infrared codes to receiver 850 comprising an infrared lightdetector, whether as time division multiplexed data or in any otherknown manner that enables receiver 850 and/or processing and storage 830to distinguish the codes. In certain ones of such embodiments, theancillary codes and locations codes are both communicated fromstationary monitor 20 as short-range and/or directional RF energy toreceiver 850 comprising an RF receiver in any known manner that enablesreceiver 850 and/or processing and storage 830 to distinguish the codes,for example, as time-division multiplexed signals, code-divisionmultiplexed signals or otherwise. In certain embodiments, the stationarydevice 20 communicates the location codes to receiver 850 and a separatedevice communicates the ancillary codes to receiver 850, for example, apresentation device (such as a television, radio or the like) maycommunicate the ancillary codes to the receiver 850 as audible-rangeacoustic data.

At the processing facility, the ancillary codes and location codesreceived from the portable monitor 800 and/or the portable monitor 800′,along with their time stamps, are processed to produce a database ofcontent exposure data for the corresponding panelist (identified bypanelist ID or portable monitor ID), indicating the content that thepanelist was exposed to and/or the content source, the times and days ofexposure and the particular location of the panelist when exposed tosuch content. In certain embodiments, the content exposure data for agiven panelist/portable monitor are matched with data collected bystationary devices acting as monitors in respective locations or otherstationary monitoring devices at such locations, to supplement thecontent exposure data for that panelist/portable monitor. These latterembodiments are useful, for example, where the stationary monitoringdevices are able to gather content presentation records having a greatertime resolution than those obtainable from the portable monitor 800.

A method of producing data representing exposure of a panelist tocontent at a predetermined location comprises supplying the panelistwith a portable monitor capable of being carried on the person of thepanelist, gathering content exposure data in the portable monitor as itis carried on the person of the panelist, gathering location data in theportable monitor as it is carried on the person of the panelist, thelocation data indicating a presence of the panelist at the predeterminedlocation and processing the gathered content exposure data and thegathered location data to produce data representing content to which thepanelist was exposed when the panelist was present at the predeterminedlocation.

FIG. 11 illustrates an embodiment of a system for gathering dataconcerning exposure of a panelist to content, wherein the panelist isprovided with two separate devices for gathering such data. Morespecifically, the panelist is provided with a first portable device 900that serves to receive ancillary codes encoding a selected channel,station, or other source of content, content identification or othercharacterizing data relating to content, and a second portable device910 that serves to receive a location code from stationary device 20.Each of the portable deices 900 and 910 is carried on the person of thepanelist to receive its respective data, and each stores its respectivedata with a time stamp.

In certain embodiments, each of the portable devices 900 and 910communicates its stored data to a processing facility separately fromthe data communicated from the other device. At the processing facility,the ancillary codes received from the first portable device 900, alongwith their time stamps, are processed to produce a database of contentexposure data for the corresponding panelist (identified by panelist IDor portable monitor ID), indicating the content that the panelist wasexposed to and/or the content source, and the times and days ofexposure. Also at the processing facility, the location codes receivedfrom the second portable device 910, along with their time stamps areprocessed to produce a database of location data, and correspondingtime/date data, for the panelist (identified by panelist ID or portablemonitor ID). The database of content exposure data and the database oflocation data are both used to produce reports in the form of stillfurther databases for indicating the content that the panelist wasexposed to and/or the content source, along with times, dates andlocations of such exposure. Such further databases take the form of dataused to provide reports as visual displays to a user, printed reports orother forms, and/or are processed with still further data, to providestill further such reports.

In certain embodiments, the data gathered by the first and secondportable devices 900 and 910 are combined in the panelist's householdand then communicated therefrom to the processing facility. FIG. 11A isa functional block diagram of such a data gathering and communicatingsystem in which the first portable device 900 assigned to the panelistcommunicates its data via a first interface 920 to a data consolidatingprocessor 930 within the panelist's household and second portable deviceassigned to the panelist communicates its data to the data consolidatingprocessor 930 via a second interface 940. The data consolidatingprocessor 930 combines the data from the first and second portabledevices 900 and 910 in a single database which it supplies tocommunications 950 which serves to communicate the consolidated datafrom the first and second devices to the processing facility, indicatedas 960 in FIG. 11A, via a network 970.

In certain embodiments, one of the first and second devices portable 900and 910 communicates the data it has gathered, including time stampdata, to the other of the first and second device 900 and 910 either bya wired connection or a wireless link, such as a Bluetooth or Zigbeelink. The one of the first and second portable devices 900 and 910 thatreceives such data from the other thereof, communicates its data to theprocessing facility 960 via the network 970, either through an interfacein the panelist's household, or by a direct link to the network 970(such as a cellular telephone link or an Internet gateway).

A method of producing data representing exposure of a panelist tocontent at a predetermined location comprises supplying the panelistwith a first portable device capable of being carried on the person ofthe panelist, gathering content exposure data in the first portabledevice as it is carried on the person of the panelist, providing thepanelist with a second portable device capable of being carried on theperson of the panelist, gathering location data in the second portabledevice as it is carried on the person of the panelist, the location dataindicating a presence of the panelist at the predetermined location andprocessing the gathered content exposure data and the gathered locationdata to produce data representing content to which the panelist wasexposed when the panelist was present at the predetermined location.

FIG. 12 illustrates a process for determining a location of a panelistcarrying portable monitor 30 of FIG. 1 proximate to presentation 15which is reproducing content acoustically. It will be appreciated thatthe use of stationary device 20 to communicate location codes to monitor30 is not required in the embodiment of FIG. 12.

As indicated in FIG. 12, stationary device 20 reads 1000 ancillary codesin acoustic content data reproduced by presentation 15 and thus includedin the ambient acoustic energy. In the alternative, stationary device 20has a wired connection to presentation device 15 or another source ofthe audio reproduced thereby to read such ancillary codes. Stationarydevice 20 stores 1010 the codes it has read with time stamps andsubsequently communicates 1020 the stored codes and their time stamps toa processing facility.

At the same time that stationary monitor 20 is reading ancillary codesfrom data that has been, or is being reproduced by presentation 15, theportable monitor 30 reads 1030 the same ancillary codes in the acousticcontent data reproduced by presentation 15. Portable monitor 30 stores1040 the codes it has read with time stamps and subsequentlycommunicates 1050 the stored codes and their time stamps to theprocessing facility.

The processing facility processes 1060 the ancillary codes andassociated time stamps from stationary device 20 and portable monitor 30to determine if the ancillary codes with corresponding time stampsmatch. If so, processing facility records data indicating such matchand/or an inference that the panelist assigned to carry portable monitor30 was present in the same area (e.g., room of the panelist's household)as stationary device 20 at the times reflected by the time stamps. Thematching process can be substantially simplified using data correlatingstationary device 20 with the panelist's household and correspondingdata for the portable monitor 30.

In certain embodiments, code detection data is produced indicating thateither an ancillary code was or was not detected at each of a pluralityof times or time periods both by stationary device 20 and portablemonitor 30. Such code detection data is produced by either or both ofstationary device 20 and portable monitor 30, and/or at the processingfacility. The code detection data for the monitor 30 and stationarydevice 20 is compared at corresponding times for a match of all or asufficiently large number or proportion of the code detection data todetermine a proximity of the monitor 30 and stationary device 20 at suchcorresponding times.

In certain embodiments, only portions of ancillary codes read byportable monitor 30 and stationary device 20 at corresponding times ortime periods are compared to determine a proximity of the portablemonitor 30 and stationary device 20. In certain ones of suchembodiments, only marker symbols detected by the monitor 30 and device20 are compared for this purpose.

FIG. 13 illustrates a further process for determining a location of apanelist carrying portable monitor 30 of FIG. 1 proximate topresentation which is reproducing content acoustically. As in theembodiment of FIG. 12, it will be appreciated that the use of stationarydevice 20 to communicate location codes to monitor 30 is not required inthe embodiment of FIG. 13.

As indicated in FIG. 13, stationary device 20 extracts 1100 signaturesfrom the ambient acoustic energy. In the alternative, stationary devicehas a wired connection to presentation device 15 or another source ofthe audio reproduced thereby to receive the audio data being reproducedand extracts signatures therefrom. Stationary device 20 stores 1110 thesignatures it has extracted with time stamps and subsequentlycommunicates 1120 the stored signatures and their time stamps to aprocessing facility.

At the same time that stationary monitor 20 is extracting signaturesfrom data that has been, or is being reproduced by presentation 15, theportable monitor 30 extracts 1130 signatures from the ambient acousticenergy, including the acoustic content data reproduced by presentation15. Portable monitor 30 stores 1140 the extracted signatures with timestamps and subsequently communicates 1150 the stored signatures andtheir time stamps to the processing facility.

The processing facility processes 1160 the signatures and associatedtime stamps from stationary device 20 and portable monitor 30 todetermine if they match. If so, the processing facility records dataindicating such match and/or an inference that the panelist assigned tocarry portable monitor 30 was present in the same area (e.g., room ofthe panelist's household) as stationary device 20 at the times reflectedby the time stamps. The matching process can be substantially simplifiedusing data correlating stationary device with the panelist's householdand corresponding data for the portable monitor 30.

Suitable techniques for extracting signatures include those disclosed inU.S. Pat. No. 5,612,729 to Ellis, et al. and in U.S. Pat. No. 4,739,398to Thomas, et al., each of which is assigned to the assignee of thepresent application and both of which are incorporated herein byreference in their entireties.

Still other suitable techniques are the subject of U.S. Pat. No.2,662,168 to Scherbatskoy, U.S. Pat. No. 3,919,479 to Moon, et al., U.S.Pat. No. 4,697,209 to Kiewit, et al., U.S. Pat. No. 4,677,466 to Led, etal., U.S. Pat. No. 5,512,933 to Wheatley, et al., U.S. Pat. No.4,955,070 to Welsh, et al., U.S. Pat. No. 4,918,730 to Schulze, U.S.Pat. No. 4,843,562 to Kenyon, et al., U.S. Pat. No. 4,450,551 to Kenyon,et al., U.S. Pat. No. 4,230,990 to Led, et al., U.S. Pat. No. 5,594,934to Lu, et al., European Published Patent Application EP 0887958 toBichsel and PCT publication WO91/11062 to Young, et al., all of whichare incorporated herein by reference in their entireties.

An advantageous signature extraction technique transforms audio datawithin a predetermined frequency range to the frequency domain by atransform function, such as an FFT. The FFT data from an even number offrequency bands (for example, eight, ten, sixteen or thirty twofrequency bands) spanning the predetermined frequency range are used twobands at a time during successive time intervals. FIG. 14 provides anexample of how pairs of the bands are selected during successive timeintervals where the total number of bands used is equal to ten. Theselected bands are indicated by an “X”.

When each band is selected, the energy values of the FFT bins withinsuch band and such time interval are processed to form one bit of thesignature. If there are ten FFT's for each interval of the audio signal,for example, the values of all bins of such band within the first fiveFFT's are summed to form a value “A” and the values of all bins of suchband within the last five FFT's are summed to form a value “B”. In thecase of a received broadcast audio signal, the value A is formed fromportions of the audio signal that were broadcast prior to those used toform the value B.

To form a bit of the signature, the values A and B are compared. If B isgreater than A, the bit is assigned a value “1” and if A is greater thanor equal to B, the bit is assigned a value of “0”. Thus, during eachtime interval, two bits of the signature are produced.

In certain embodiments, both portable monitor 30 and stationary device20 process data representing ambient acoustic energy at correspondingtimes or time periods to produce ambient acoustic energy change datarepresenting one or more of energy changes in one or more frequencybands or intervals, with or without comparison to other time periods orintervals of the same or other frequency bands or intervals. In certainones of such embodiments, acoustic energy or power transitions over timegreater than a predetermined value (such as 20 db, 30 db, or other) arestored. Such comparisons can be made, for example, to average energy orpower levels for one or more time periods or intervals and/or frequencyintervals or bands.

In certain embodiments, data is produced by portable monitor 30 andstationary device 20 produce energy or power trend data indicatingchanges in ambient acoustic power or energy over time in one or morefrequency bands or intervals. In each such embodiment and variantsthereof, the data representing ambient acoustic energy changes gatheredby device 20 and monitor 30 are compared to determine if the same werein proximity at one or more times, time periods or intervals.

Although various embodiments have been described with reference to aparticular arrangement of parts, features and the like, these are notintended to exhaust all possible arrangements or features, and indeedmany other embodiments, modifications and variations will beascertainable to those of skill in the art.

What is claimed is:
 1. A method for gathering audience measurement data,comprising: gathering, via a stationary monitoring system, first dataconcerning exposure to media output by a media receiver, whereingathering the first data comprises collecting a first code encoded inthe media; gathering second data concerning exposure to the media outputby the media receiver with a portable monitor carried on the person of auser, wherein the second data comprises a second code encoded in themedia; gathering, via the portable monitor, location data encoded in themedia by the stationary monitoring system, the location data providinginformation on a physical location of the portable monitor; andproducing the audience measurement data concerning exposure to the mediaoutput by the receiver from the first data, the second data, and thelocation data.
 2. The method of claim 1, wherein the media receivercomprises the stationary monitoring system.
 3. The method of claim 2,wherein the stationary monitoring system comprises software running on aprocessor of the media receiver.
 4. The method of claim 3, wherein themedia receiver comprises at least one of a media recording device, amedia playback device, a user-operated recording device, a user-operatedplayback device, a television, television broadcast reception equipment,a radio, radio broadcast reception equipment, a video cassette player, adigital video disk player, a digital video recorder, a gaming device, apersonal video player, an audio cassette player, a compact disk player,a personal audio player, an electronic book, and a personal computer. 5.The method of claim 1, wherein the media comprises at least one oftelevision media, radio media, video cassette media, digital video diskmedia, digital video recorder media, personal video player media, audiocassette media, compact disk media, personal audio player media, audio,video, digital audio, digital video, gaming media, streaming media,Internet-supplied media, and personal computer media.
 6. The method ofclaim 1, wherein gathering the first data comprises gathering firstmedia reception data comprising an indication of at least one of astation received by the media receiver, a channel received by the mediareceiver, and a program received by the media receiver, whereingathering the second data comprises gathering second media receptiondata comprising an indication of at least one of a station, a channel,and a program to which the user was exposed.
 7. The method of claim 1,further comprising gathering at least one of portable monitoridentification data, audience member identification data and audiencemember demographic data, and producing the audience measurement dataconcerning exposure to the media based on the at least one of theportable monitor identification data, the audience member identificationdata and the audience member demographic data.
 8. The method of claim 1,further comprising gathering, via the portable monitor, second locationdata encoded in the media by a second stationary monitoring system todetect whether the user is exposed to the media by the stationarymonitoring system or the second monitoring system.
 9. The method ofclaim 1, further comprising matching the second data gathered by theportable monitor with the first data gathered by the stationarymonitoring system to supplement the second data with the first data, thefirst data having a greater time resolution than the second data.
 10. Asystem for gathering audience measurement data, comprising: a stationarymonitoring system to gather first data concerning exposure to media froma media receiver, the stationary monitoring system to gather the firstdata by gathering a first code encoded in the media; a portable monitorto gather second data concerning exposure to media output by the mediareceiver, the portable monitor to gather the second data by gathering asecond code encoded in the media; wherein the portable monitor is togather location data encoded in the media by the stationary monitoringsystem, the location data providing information on a physical locationof the portable monitor; and a processor to receive the first data, thesecond data, and the location data and to produce audience measurementdata concerning exposure to the media output by the media receiver basedon the first data, the second data, and the location data.
 11. Thesystem of claim 10, wherein the media receiver comprises the stationarymonitoring system.
 12. The system of claim 11, wherein the stationarymonitoring system comprises software running on a processor of the mediareceiver.
 13. The system of claim 12, wherein the media receivercomprises at least one of a media recording device, a media playbackdevice, a user-operated recording device, a user-operated playbackdevice, a television, television broadcast reception equipment, a radio,radio broadcast reception equipment, a video cassette player, a digitalvideo disk player, a digital video recorder, a gaming device, a personalvideo player, an audio cassette player, a compact disk player, apersonal audio player, an electronic book, and a personal computer. 14.The system of claim 10, wherein the media comprises at least one oftelevision media, radio media, video cassette media, digital video diskmedia, digital video recorder media, personal video player media, audiocassette media, compact disk media, personal audio player media, audio,video, digital audio, digital video, gaming media, streaming media,Internet-supplied media, and personal computer media.
 15. The system ofclaim 10, wherein the first data comprises an indication of at least oneof a station received by the media receiver, a channel received by themedia receiver, and a program received by the media receiver, the seconddata comprises an indication of at least one of a station, a channel,and a program to which a user was exposed.
 16. The system of claim 10,wherein the processor is to gather at least one of portable monitoridentification data, audience member identification data and audiencemember demographic data and is to produce the audience measurement dataconcerning exposure of the media based on at least one of portablemonitor identification data, audience member identification data andaudience member demographic data.
 17. A computer readable storage discor storage device comprising instructions that, when executed cause amachine to at least: collect, via a stationary monitoring system, firstdata concerning exposure to media output by a media receiver, whereingathering the first data comprises collecting a first code encoded inthe media; collect, via a portable monitor carried on the person of auser, second data concerning exposure to the media output by the mediareceiver, wherein the second data comprises a second code encoded in themedia; collect, via the portable monitor, location data encoded in themedia by the stationary monitoring system, the location data providinginformation on a physical location of the portable monitor; and produceaudience measurement data concerning exposure to the media output by thereceiver from the first data, the second data, and the location data.18. The computer readable storage disc or storage device of claim 17,wherein the instructions, when executed cause the machine to collect,via the portable monitor, second location data encoded in the media by asecond stationary monitoring system and to detect whether the user isexposed to the media by the stationary monitoring system or the secondmonitoring system.
 19. The computer readable storage disc or storagedevice of claim 17, wherein the instructions, when executed, cause themachine to match the second data gathered by the portable monitor withthe first data gathered by the stationary monitoring system tosupplement the second data with the first data, the first data having agreater time resolution than the second data.
 20. The computer readablestorage disc or storage device of claim 17, wherein the media receivercomprises the stationary monitoring system.